Background: Addressing gene-gene interactions is essential in defining a trait implicating complex disease-related mechanisms. In this study, we aimed to explore both main effects of single-locus and multi-locus interactions to test the hypothesis that the ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1) and perilipin (PLIN) genes may contribute to the etiology of type 2 diabetes (T2D) independently and/or through complex interactions in a Taiwanese population.
Methods: There were 416 patients with a diagnosis of T2D and 188 age- and sex-similar control subjects. To investigate gene-gene interactions, we used both the generalized multifactor dimensionality reduction method and logistic regression models.
Results: Allelic and genotypic analyses showed significant main effects of ENPP1 rs1044498 (P = 0.000005 and 0.00007, respectively) on the risk of T2D after Bonferroni correction (P < 0.05/2 = 0.025). Compared to the carrier of the AA genotype of the ENPP1 rs1044498 polymorphism, the likelihood of T2D was 2.442 (95% confidence interval, 1.592-3.747) for the carrier of combined AC+CC genotypes after adjustment of sex and body mass index. In addition, the carriers of AA variant in the PLIN rs894160 polymorphism had a higher risk to T2D than those with the combined AG+GG variants (adjusted odds ratio, 1.856; 95% confidence interval, 1.106-3.115) after adjustment of sex and body mass index. Furthermore, the significant 2-locus (P = 0.001) generalized multifactor dimensionality reduction model was identified between ENPP1 and PLIN. Analyses using logistic regression models confirmed the gene-gene interaction.
Conclusions: The results suggest that the ENPP1 and PLIN genes may contribute to the risk of T2D independently and/or in an interactive manner in a Taiwanese population.